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Biomedical subjects

J Hassan

Publications and source records attributed to J Hassan.

At least 37 records · Page 2Linked to original sources
PubMed1996

Umbilical vein to artery ratio in fetuses with single umbilical artery.

In fetuses with single umbilical artery (SUA) the entire blood flow to the placenta is transported through only one umbilical artery, resulting in a compensatory increase of the arterial diameter. In order to establish whether umbilical vessel size could be used as an additional ultrasonographic criterion for prenatal diagnosis of SUA, we measured umbilical vein and umbilical artery diameters in 55 fetuses with SUA and in 55 with a normal three-vessel cord matched for gestational age. In all but one fetus with SUA, the diameter of the umbilical artery was greater than 50% of that of the umbilical vein, resulting in an umbilical vein to umbilical artery ratio of < or = 2. In contrast, none of the fetuses with a three-vessel cord had a ratio of < or = 2. Increasing diameter of the umbilical artery with no modification of the diameter of the vein is a characteristic prenatal ultrasonographic feature of SUA, making this observation a useful technique for the detection of this vascular anomaly in utero.

Female↗
PubMed1996

Increased numbers of CD5+ B cells and T cell receptor (TCR) gamma delta+ T cells are associated with younger age of onset in rheumatoid arthritis (RA).

Patients presenting with RA before the age of 45 years (younger onset) are known to have more aggressive disease compared with patients presenting after the age of 65 years (older onset). Coordinated expansion of circulating CD5+ B cell and TCR gamma delta+ T cell levels has been reported in patients with RA. This study assesses the peripheral blood levels of these two cell types in RA patients with younger and older onset of disease. CD5+ B cell levels were significantly elevated in the younger onset RA group (26.6+/-4.5%) compared with the older onset RA group (14.2+/-1.2%; P<0.01). TCR gamma delta+ T cell levels were also significantly raised in the young patients (4.0+/-0.9%) compared with elderly patients (1.6+/-0.2%; P<0.01). T cell levels (CD3+) were similar in both groups (young 66.4+/-3.3%; old 74.3+/-3.4% (mean+/-s.e.m.); NS). Total B cell levels (CD19+) were also similar in these groups (7.7+/-0.7% versus 8.9+/-1.8%; NS). A significant positive correlation was observed between the CD5+ B and TCR gamma delta+ T cell types in the patients (r=0.72, P<0.05). Compared with age-matched normal controls, the younger onset patients had similar CD5+ B cell and TCR gamma delta+ T cell levels to the elderly controls (CD5+ B cells 30.2+/-3.0%; TCR gamma delta+ T cells 3.0+/-0.8%). Conversely, older onset RA patients had CD5+ B cell levels similar to the young controls (12.3+/-1.9%). Spontaneous in vitro synthesis of immunoglobulins (IgM, IgA and IgG) and rheumatoid factors (IgM and IgA isotypes) were not significantly different in both patient groups. The coordinate expansion of circulating CD5+ B cells and gamma delta+ T cells seen in patients with RA presenting before 45 years of age and not after 65 years of age may suggest a potential role for these cells in more aggressive disease states.

Adult↗
PubMed1995

Ablation of acardiac twin by alcohol injection into the intra-abdominal umbilical artery.

BACKGROUND: Twin reversed arterial perfusion sequence is a rare complication of monochorionic twinning, in which the normal pump twin perfuses the abnormal acardiac twin in a reversed fashion via an artery-to-artery placental anastomosis. Mortality in the normal twin exceeds 50% as a result of preterm labor, polyhydramnios, and congestive heart failure. CASE: A twin pregnancy complicated by the twin reversed arterial perfusion sequence developed early hemodynamic decompensation in the pump twin with increasing size of the acardiac twin. Ablation of the acardiac twin at 23 weeks' gestation was achieved successfully by injecting 1 mL of absolute alcohol into the intra-abdominal portion of the single umbilical artery. CONCLUSION: Direct ultrasound-guided intravascular injection of absolute alcohol is an easy and straightforward technique to occlude circulation to the acardiac twin. This vessel can be identified easily by color Doppler ultrasonography away from the main venous trunk. Selection of this target, rather than occlusion at the level of the umbilical cord, could reduce the risks of cord accidents and inadvertent intravenous injection of the ablative material.

Abdomen↗
PubMed1995

Abnormal innervation and altered nerve growth factor messenger ribonucleic acid expression in ureteropelvic junction obstruction.

The pathophysiology of ureteropelvic junction obstruction is unknown. Using specific antibodies, we studied specimens from 35 cases of ureteropelvic junction obstruction and 32 of normal ureteropelvic junction by immunohistochemistry using protein gene product 9.5 (a general neuronal marker), S100 (a supporting cell marker), synaptophysin (a neuromuscular junction marker) and nerve growth factor receptor. Nerve growth factor expression was examined at the messenger ribonucleic acid (mRNA) level using reverse transcription-polymerase chain reaction technique in 11 ureteropelvic junction obstruction specimens and 7 controls. The most striking finding was the marked reduction of protein gene product 9.5, synaptophysin and nerve growth factor receptor staining positive nerve fibers in the muscle layers of ureteropelvic junction obstruction compared to the normal ureteropelvic junction. Supporting nerve cell fibers (S100) were preserved in cases of ureteropelvic junction obstruction and normal ureteropelvic junction. A significantly less intense signal for nerve growth factor mRNA was found in the ureteropelvic junction obstruction specimens compared to normal ureteropelvic junction. These findings suggest that defective innervation may have an important role in the pathogenesis of ureteropelvic junction obstruction, and decreased nerve growth factor mRNA expression may be important in the etiology of ureteropelvic junction obstruction.

Base Sequence↗
PubMed1995

Signalling via CD28 of human naive neonatal T lymphocytes.

Accessory molecules play a crucial role in the development of the T cell response to antigenic challenge. We have examined the role of CD28 in modulating the 'naive' neonatal T cell response to anti-CD2-mediated activation. To compare the role of CD28, neonatal and adult T cells were stimulated with a pair of mitogenic anti-CD2 antibodies in the presence or absence of anti-CD28 MoAb. With anti-CD2 alone, neonatal T cells proliferated slightly but produced no detectable IL-2, whereas adult T cells proliferated vigorously, with significant IL-2 production. Costimulation with anti-CD28 MoAb greatly enhanced the proliferative response of neonatal T cells to levels equivalent to those of adult T cells, whereas adult T cells showed only slight increases. Although IL-2 secretion was increased in the presence of anti-CD28 MoAb, neonatal T cell IL-2 production remained lower than in adults. In contrast, enhancement of IL-2 mRNA expression in neonates was similar to adult levels. Anti-CD28 MoAb costimulation increased NF kappa B levels in neonates, albeit to levels lower than that of adults. The cellular mechanism governing the diminished proliferative response of neonatal T lymphocytes to anti-CD2 may therefore be due to decreased NF kappa B induction, reduced IL-2 mRNA expression and deficient IL-2 production. Although anti-CD28 MoAb costimulation enhances all of the above signals, NF kappa B and IL-2 levels remain lower than in adults, suggesting the need for further activation requirements in the neonate.

Adult↗
PubMed1994

Multiplicities of secondaries in nuclear interactions, induced by 20Ne, 40Ar and 56Fe nuclei at 0.1-0.5 GeV/nucleon.

Multiplicities of various species of charged secondaries produced in inelastic interactions of 20Ne, 40Ar and 56Fe nuclei with emulsion nuclei at 0.1-0.5 GeV/nucleon have been measured. The data obtained are compared with the results for interactions of higher energy nuclei with emulsion nuclei. The dependences of the nucleus-nucleus interaction parameters on masses and energies of colliding nuclei are examined.

Argon↗
PubMed1994

Interleukin-1 augments the diminished interleukin-2 mRNA expression and proliferative response of neonatal T lymphocytes to anti-CD2 antibodies.

Expression of IL-2 mRNA by unstimulated and stimulated purified T cells and mononuclear cells from adult and cord blood was investigated in an attempt to better understand the underlying defective neonatal host immune defense system. Using RNA dot-blot analysis, IL-2 mRNA expression in anti-CD2-stimulated neonatal T cells revealed significantly reduced levels when compared to adult T cells (P < 0.01). Purified neonatal T cells also showed a significantly reduced proliferative response to anti-CD2 antibodies (P < 0.01). Addition of IL-1 beta enhanced the hyporesponsiveness of neonatal T cells at both the level of proliferation and IL-2 mRNA expression. Unseparated mononuclear cells from adult and cord blood revealed similar IL-2 mRNA levels and proliferation when activated by anti-CD2 stimulation. The reduced IL-2 mRNA expression observed in neonatal T cells may explain, in part, the difference in host defense between the newborn and adult during states of increased demand such as infection.

Adult↗
PubMed1994

High prevalence of thyroid function test abnormalities in chronic schizophrenia.

The thyroid status of 249 patients with chronic schizophrenia (males = 136, females = 113) with a median age of 36 years (range: 16 to 58 years) and a median duration of hospitalisation of 10 years (range: 1 to 30 years) was assessed. Thyroid antibodies (TAb) were found in 51 patients (20%). In female patients, 32 (28%) were TAb positive compared to 13% (n = 152, p = 0.01) in healthy female blood donors. In male patients, the prevalence of TAb was 14% compared to 7% (n = 449, p = 0.01) in healthy male blood donors. Of the 183 patients who had thyroid hormone measurements, 60% had normal test, 5% had elevated TSH and 17% had low TSH. The T4, FT41 and FT31 were significantly lower in those with low or high TSH (p < 0.001) compared to those with normal TSH. Of the 143 patients with normal TSH, 33 (23%) had low T3. In conclusion, there is a spectrum of thyroid function test abnormalities in chronic schizophrenia; this may be related to an abnormality in the central regulation of the hypothalamo-pituitary thyroid axis as well as at the peripheral level. However the association between chronic schizophrenia and the presence of thyroid antibodies, and the clinical relevance of these biochemical abnormalities, are still not clear.

Adolescent↗
PubMed1994

Serum IgA and IgG subclasses during treatment for acute respiratory exacerbation in cystic fibrosis: analysis of patients colonised with mucoid or non-mucoid strains of pseudomonas aeruginosa.

Patients with cystic fibrosis (CF) have a high prevalence of Pseudomonas aeruginosa infection which causes chronic infection of the mucosal surfaces of the lung. This results in recurrent immune stimulation and hypergammaglobulinemia. The present study examines the levels of circulating Ig classes, IgG and IgA subclasses in 13 adult patients with CF during acute pulmonary infection and post-exacerbation. Total serum IgG levels were raised in the patients during infection and post-treatment when compared to the normal range (mean +/- SEM: 17.21 +/- 1.4 g/l vs 16.45 +/- 1.5 g/l respectively; normal range 8-16 g/l). In contrast, total IgM (2.6 +/- 0.26 vs 2.69 +/- 2.74 g/l; normal range 0.6-2.8 g/l) and IgA levels (2.5 +/- 0.52 vs 2.41 +/- 0.48 g/l; normal range 0.5-4 g/l) remained unchanged when examined during all stages of the disease. Of the 13 patients studied, 69%, 39% and 31% had IgG, IgM and IgA levels respectively raised above the normal range values. The mean levels of individual IgG subclasses examined in this group of patients revealed values within the normal ranges, however IgG2 and IgG3 were increased in 31% and 46% of patients. Individual IgG3 levels fell in 77% (10/13) and IgG4 in 62% (8/13) of the patients post-exacerbation. With regard to IgA subclasses, significant reduction in the IgA1 levels were observed post treatment (3687 +/- 539 mg/l vs 2713 +/- 498 mg/l, p < 0.01). In contrast, IgA2 levels were increased from 279 +/- 49 mg/l to 421 +/- 69 mg/l, although statistical significance was not reached. Upon antibiotic treatment for infection, the findings in this study show that IgA1 which is susceptible to bacterial proteases is reduced with a concommitant increase in the protease resistant IgA2 subclass. Moreover, patients colonised with non-mucoid strains of P. aeroginosa had higher total IgA levels due to the raised IgA1 subclass whereas they had lower IgG levels due to low IgG2 and IgG4 subclasses.

Acute Disease↗
PubMed1994

The return of fertility after discontinuation of oral contraception in Malaysian women.

The return of fertility after discontinuation of oral contraception was studied in a cross-sectional survey of 61 patients who were desirous of a further pregnancy. For controls, 380 women who did not take any oral contraception were used. Cumulative conception rates in the pill users were reduced but not significantly during the first three (p = 0.15) and six months (p = 0.20). By 12 months this difference was negligible (p = 0.28). We conclude that there is no significant delay in return of fertility following cessation of oral contraception in our group of Malaysian women.

Adolescent↗
PubMed1992

Prevalence of anti-Fab antibodies in patients with autoimmune and infectious diseases.

Sensitive ELISA were devised to examine the specificity of circulating IgM and IgA autoantibodies for whole human IgG, Fc and Fab fragments of human IgG. Sera from patients with autoimmune and infectious conditions such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), tuberculosis (TB), infectious mononucleosis (IM) and cystic fibrosis (CF) were studied. Results of the ELISA assays using whole human IgG as antigen revealed that a proportion of patients in each of the groups studied had circulating IgM and IgA rheumatoid factors (RF). Fifteen normal individuals studied were negative. In the latex positive RA group, IgM RF and IgA RF had primarily anti-Fc reactivity (100% and 93% respectively), although 3/15 patients also showed IgM anti-Fab reactivity and one patient had high IgA anti-Fab activity. Patients with SLE and TB who had detectable RF levels also revealed predominantly anti-Fc specificity. In contrast, examination of 25 patients with IM showed positivity for IgM RF activity in 8% of patients using whole IgG as antigen, 24% positivity using purified Fc fragments as antigen and 45% positivity when plates were coated with Fab fragments. Similarly, a large number of CF patients (54%) also showed predominantly IgM anti-Fab activity. Of interest, 69% of the CF patients who were all studied at the time of bacterial infection had detectable IgA RF levels, with 46% of these patients showing both IgA anti-Fc and anti-Fab activity. These findings suggest that autoantibody specificities in autoimmune and infectious diseases are different.

Adolescent↗
PubMed1991

Effect of gold therapy on CD5+ B-cells and TCR gamma delta+ T-cells in patients with rheumatoid arthritis.

Circulating CD5+ B-cell levels in 15 patients with rheumatoid arthritis (RA) not receiving remittive therapy was significantly increased when compared to 17 normal controls (mean +/- SE: RA, 19.7 +/- 2.85%; controls, 11.6 +/- 1.67%; P less than 0.02). In contrast, 24 patients with RA receiving gold sodium thiomalate therapy (GST) had similar CD5+ B-cell levels (11.88 +/- 1.65) when compared to controls and significantly reduced levels when compared to the RA group not receiving remittive agents (P less than 0.01). Furthermore, TCR gamma delta+ T-cell levels were also assessed in these patients groups. These values were not significantly different between any of the groups (controls, 4.46 +/- 1.36%; GST, 6.88 +/- 1.73%; RA, 2.73 +/- 0.55%), although 42% of the GST treated group had gamma delta+ T-cell levels higher than the entire untreated RA group. No correlation was observed between the levels of TCR gamma delta + T-cells and CD5+ B-cells in any of these groups. These results suggested that therapy does influence the level of CD5+ B-cells and gamma delta+ T-cells in these patients.

Antigens, CD↗
PubMed1991

Induction of IgM and IgM-rheumatoid factor synthesis in vitro by indomethacin.

Indomethacin, which is thought to exert its therapeutic effect by inhibiting the synthesis of PGE2, is a commonly used first-line agent in the treatment of rheumatoid arthritis (RA). However, the effect of this drug on the humoral immune response in RA remains unclear. In this study, modulation of the in vitro synthesis of IgM and IgM-rheumatoid factor (RF) by indomethacin and prostaglandin E2 was examined in 11 patients with active RA and 10 normal controls. Indomethacin at a final concentration of 1 microgram/ml significantly enhanced IgM production (P less than 0.01) and RF production (P less than 0.02) in Staphylococcus aureus Cowan I (SAC) stimulated RA cultures when compared to controls in whom no net enhancement effect was observed. In the patients, this increase in IgM production was more pronounced than the corresponding increase in RF synthesis (P = 0.078), suggesting that IgM and IgM-RF-secreting RA plasma cells have different susceptibilities to PGE2 mediated suppression. Nonetheless, addition of PGE2 (10(-8) M final concentration) to the cultures inhibited IgM and RF production to a similar degree in the patient and control cultures. These findings demonstrate that PGE2 causes suppression of IgM and IgM auto-antibody production in vitro and that inhibition of endogenous PGE2 synthesis in RA patients treated with indomethacin results in a marked increase in the production of these antibodies.

Arthritis, Rheumatoid↗
PubMed1989

Lymphoid irradiation in intractable rheumatoid arthritis. Long-term followup of patients treated with 750 rads or 2,000 rads.

Twenty patients with intractable rheumatoid arthritis were randomized to receive 750 or 2,000 rads of lymphoid irradiation (LI) in a double-blind comparative study, and were followed for a maximum of 48 months (mean 40 months) after treatment. During followup, sustained immunomodulation (including lymphopenia, particularly of the T helper cell subset; reduced ratio of helper cells to suppressor cells; and impaired in vitro lymphocyte proliferation in response to phytohemagglutinin and pokeweed mitogen) was observed. Significant improvements in early morning stiffness, Ritchie articular index, pain score, grip strength, and 15-meter walk time were observed in both treatment groups, but these were not sustained through the followup period. Progressive joint damage was observed radiologically in both groups during followup. Thus, LI induced sustained immunosuppression, but resulted in only short-lived clinical improvement and was associated with progressive joint erosion in these patients.

Arthritis, Rheumatoid↗
PubMed1989

Expression and regulation of the HLA-DR antigen on circulating monocytes isolated from patients with rheumatoid arthritis.

Using a modified radioimmunoassay, surface labeling of HLA-DR antigens on monocytes revealed reduced densities in patients with active rheumatoid arthritis (RA) (P less than 0.001) and in gold-treated patients (P less than 0.01) versus normal controls. Significant enhancement of DR antigen expression (P = 0.01), with values similar to those of normal monocytes, occurred in patient monocytes preincubated at 37 degrees C overnight, but not in monocytes preincubated at 4 degrees C. This suggested that a temperature-dependent metabolic process is required to enhance antigen expression. The addition of cycloheximide totally inhibited the enhancement of DR antigen density. Incubation of monocytes with exogenous prostaglandin E2 (10(-5)M final concentration) caused a reduction of DR densities on control and on RA monocytes, although this decrease was more marked in the controls. Addition of indomethacin did not affect DR antigen levels on control monocytes, but greatly enhanced the expression of DR antigens on RA monocytes. When HLA-DR antigen levels were estimated in detergent-solubilized membrane preparations, monocytes from patients with active RA demonstrated normal-to-increased densities compared with control monocytes. Thus, although RA monocytes possess a normal ability to synthesize DR molecules, surface expression of these molecules is inhibited; this inhibition may be mediated by prostaglandin E2 acting as a negative suppressive signal.

Arthritis, Rheumatoid↗